JP5097175B2 - Wireless receiver and test method thereof - Google Patents

Description

  The present invention relates to a radio reception apparatus and a test method therefor, and more particularly to a normality confirmation method for a radio apparatus.

  In order to confirm the normality of the radio receiver, it is necessary to test two components, the receiving circuit and the receiving antenna.

The normality confirmation of the receiving circuit is performed as follows.
A part of the output signal of the transmitter is branched and input to the receiver, and the normality of the receiver is confirmed by measuring the gain of the receiver <Folding test> (Patent Document 1).
For example, a test terminal (TAT) is mounted inside the wireless device, and a reception signal is input to the receiver from here to measure the reception sensitivity of the receiver. <TAT method> (Patent Document 2)
The normality of the antenna is confirmed as follows.
A signal (for example, an output signal of a transmitter) is input to the antenna, the reflected power from the antenna is measured, and the VSWR of the antenna is measured from the ratio of the input power and the reflected power.

JP 2002-246978 A JP 2005-151189 A

  High reliability is required for mobile communication systems. For this reason, it is important that when a failure occurs in the wireless device constituting the failure, the failure can be detected accurately and the normality of the wireless device can be confirmed.

  Various test apparatuses for confirming the normality of the radio apparatus have been realized. However, when attention is paid to detection of a failure between the receiver and the receiving antenna, there are the following problems.

  In detecting a failure of a receiver, for example, a loopback test described in Patent Document 1 is often used. This method has a problem that it cannot be applied to an FDD (Frequency Division Duplex) method with different transmission and reception frequencies because a part of the output signal of the transmitter is branched and input to the receiver. Alternatively, as described in Patent Document 2, a method of mounting a test terminal inside a wireless device is conceivable. However, since the test terminal is expensive and has a large circuit scale, There are many issues regarding the viewpoint.

  On the other hand, the normality of the antenna is generally confirmed by measuring a VSWR (Voltage Standing Wave Ratio) and confirming that the value is within a predetermined range. In the VSWR measurement, a method of measuring the reflected power from the antenna of the input signal to the antenna from the transmitter and calculating the VSWR from the ratio of the input power and the reflected power is often used. In this method, although the VSWR of the antenna connected to the transmitter and the receiver can be measured, there is a problem that the VSWR of the antenna connected only to the receiver cannot be measured. For example, in the case of a wireless device composed of one transmission system and two reception systems, one transmission / reception shared antenna and one reception antenna, a total of two antennas, are connected. In this case, the VSWR of the reception antenna is It cannot be measured.

  A wireless receiver and a test method thereof according to the present invention include a directional coupler connected to an antenna, a PN code generation circuit that generates a PN code, and DA conversion that converts the generated PN code into a test signal that is a spread spectrum signal And a test signal generator having a switch for guiding the test signal to the directional coupler, a forward direction S / of the test signal input through the directional coupler and passing through the same path as the main signal input from the antenna A receiver including a PN code demodulator that measures N and a control unit that determines whether the measured forward S / N is within the first predetermined range are provided.

  According to another aspect of the wireless receiver of the present invention and the test method thereof, a PN code demodulator included in the receiver includes a main signal input via a directional coupler, reflected by the antenna, and input from the antenna. The reflection direction S / N of the test signal passing through the same path is further measured, and the control unit has the antenna VSWR obtained from the measured forward direction S / N and reflection direction S / N within the second predetermined range. It is determined whether or not.

  According to the disclosed radio receiving apparatus and its test method, normality confirmation of the radio receiver can be realized easily and at low cost.

It is a block diagram of a radio base station apparatus. It is a block diagram of a receiver normality confirmation function. It is a sequence diagram of a receiver normality confirmation system. This is the path of the test signal in the case of SW setting 1. This is a path of a test signal in the case of SW setting 2.

  Embodiments of the present invention will be described below with reference to the drawings, taking as an example a radio base station that includes one transmitter and two receivers and enables diversity reception. Note that this antenna configuration is merely an example, and the present embodiment does not depend on the number and configuration of antenna systems of the wireless device, and can be applied to wireless devices with other antenna configurations.

  FIG. 1 shows the configuration of a radio base station. The radio base station 100 includes a radio signal transmission / reception unit 110, a modulation / demodulation processing unit 111, a line interface unit 112, and a base station control unit 113. The wireless signal transmission / reception unit 110 is connected to a transmission / reception shared 0-system antenna 114 and a reception-use 1-system antenna 115, a 1-system transmitter 132 and a 2-system receiver (0-system receiver 133, 1-system receiver). 134). Furthermore, it comprises a DUP (duplexer) 130 that separates the downlink radio signal 120 and the uplink radio signal 121, and a BPF (band pass filter) 131 that limits the pass band of the uplink radio signal 121. The transmitter 132 converts the downlink baseband signal 125 input from the modulator 135 into the downlink radio signal 122. The 0-system receiver 133 converts the uplink radio signal 121 transmitted from the terminal 101 into the uplink baseband signal 126, and the 1-system receiver 134 converts the uplink radio signal 121 transmitted from the terminal 101 into the uplink baseband signal 127. To do. The modulation / demodulation processing unit 111 includes a modulator 135 and a demodulator 136, and modulates and demodulates data. The line interface unit 112 is an interface between the radio base station 100 and the network 102. The base station control unit 113 has a monitoring / control function for the radio base station 100. The maintenance terminal 103 is connected to the base station control unit 113 via the network 102 and has a function of remotely monitoring and controlling the radio base station 100.

  FIG. 2 shows a receiver and a test circuit that realizes normality confirmation of the receiver. The receiver includes an LNA (low noise amplifier) 201, a BPF (bandpass filter) 202, an AMP (amplifier) 203, an ADC (A / D converter) 204, and an RX-BB (reception baseband) 205. The LNA 201 amplifies the received signal with low distortion, and the BPF 202 attenuates unnecessary signal components other than its own band. Further, the received signal is amplified by the AMP 203 and the input signal is converted from an analog signal to a digital signal by the ADC 204. The RX-BB 205 performs quadrature demodulation and band limitation on the digital reception signal, and outputs the reception signal to the demodulator 136. The above is the description of the 0-system receiver 133, but the description of the 1-system receiver 134 is omitted because it has the same configuration.

  The receiver normality confirmation function of the present embodiment is realized by mounting a test signal generation unit 220 and CPLs (directional couplers) 225 and 226 inside the wireless device. The receiver test circuit 220 includes a PNGEN (PN code generator) 221, a DAC (D / A converter) 222, and a SW 223. The PNGEN 221 generates a PN code for receiver testing. The DAC 222 converts the PN code input from the PNGEN 221 into an analog test signal (spread spectrum signal). The SW 223 selects a path for outputting the test signal input from the DAC 222. In a normal wireless device, RX-BB 205/215 includes only main signal BB 206/216, but in this embodiment, a PN code demodulator that demodulates the test signal generated by test signal generation unit 220 here. By installing 207/217, the receiver normality confirmation function is realized.

  The test signal generated by the test signal generation unit 220 is input to the 0-system receiver 133 via the CPL 225. In the case of system 1, the signal is input to system 1 receiver 134 via CPL 226. On the other hand, the main signal input from the antenna is input to the 0-system receiver 133 via the 0-system antenna 114, the CPL 225, and the DUP 130 in the case of the 0-system. In the case of system 1, the signal is input to system 1 receiver 134 via system 1 antenna 115, CPL 226, and BPF 131. That is, the test signal is input to the 0-system receiver 133 or the 1-system receiver 134 in a state of being superimposed on the main signal of each system, but the power of the test signal is extremely small for the reason described later. Can be ignored. For this reason, the normality check according to the present embodiment has no influence on the service operation.

  The main signal and the test signal input to the 0-system receiver 133 are input to the RX-BB 205. The signal input to RX-BB 205 is distributed to main signal BB 206 and PN code demodulator 207, performs quadrature demodulation of the main signal, band limitation, etc., and outputs a received main signal to demodulator 136. On the other hand, the PN code demodulator 207 performs quadrature demodulation and despreading processing of the test signal to obtain the S / N of the test signal. The above is the description of the 0-system receiver 133, but the description of the 1-system receiver 134 is omitted because it has the same configuration.

  In order to reduce the test signal power, it is necessary to increase the spreading gain. By increasing the number of in-phase additions, that is, by increasing the measurement time, the diffusion gain can be increased. For example, in a cdma2000 system with a chip rate of 1.2288 [Mchips / s], when the measurement time is 1 Frame (26.7 [ms]), the spreading gain is 45 dB. By obtaining such a large spreading gain, the power of the test signal can be reduced, which is an advantage that the test signal is a spread spectrum signal.

  Hereinafter, a receiver failure detection method according to this embodiment will be described with reference to FIGS. 1, 2, and 3. FIG. 3 is a sequence diagram of the receiver normality confirmation method. Since the 0 system and the 1 system can be diagnosed by the same procedure, FIG. 3 and the following description explain the normality confirmation procedure of the 0 system receiver 133 and the 0 system antenna 114, and the 1 system receiver 134. The description of the first system antenna 115 is omitted. Also, since Ack for the request usually exists, it is omitted.

  The normality check of the receiver is started, for example, when the maintenance worker inputs a command for executing the normality check of the receiver to the maintenance terminal 103. The receiver normality diagnosis execution instruction includes designation of a base station to be tested and designation of a receiver to be diagnosed (for example, sector and system).

  In step 301, the maintenance terminal 103 notifies the base station control unit 113 of the designated radio base station 100 of a normality confirmation start instruction including identification information (eg, sector and system) of the designated receiver. Note that the specification of the receiver to be diagnosed may be omitted, and the tests may be sequentially performed on all receivers in the radio base station 100 or predetermined receivers.

  In step 302, the base station control unit 113 instructs the test signal generation unit 220 to set the SW 223. In step 303, the test signal generator 220 sets SW223 to terminal 1 (SW setting 1).

  In step 304, the base station control unit 113 instructs the test signal generation unit 220 to transmit a test signal. In step 305, the test signal generation unit 220 operates the PNGEN 221 and transmits a test signal. The PN code generated by the PNGEN 221 is converted into an analog signal by the DAC 222, supplied via the SW 223 and the CPL 225, and input to the 0-system receiver 133 (path 240 in FIG. 4). The test signal takes the same path as the main signal received from the antenna 114 inside the 0-system receiver 133.

  In step 306, the base station control unit 113 requests the 0-system receiver 133 to report the S / N of the received test signal. In step 307, the 0-system receiver 133 demodulates the test signal by the PN code demodulator 207 and reports the S / N of the received test signal to the base station control unit 113. In Step 308, the base station control unit 113 records the reported received S / N value in the RAM 138. The value to be recorded here is “forward S / N”.

  In step 309, the base station control unit 113 instructs the test signal generation unit 220 to set the SW 223. In step 310, the test signal generation unit 220 sets SW223 to terminal 2 (SW setting 2). The PN code generated by the PNGEN 221 is converted into an analog signal by the DAD 222 and input to the 0-system antenna 114 via the SW 223 and the CPL 225. A signal reflected by the 0-system antenna 114 is input to the 0-system receiver 133 via the CPL 225 and the DUP 130 (route 241 in FIG. 5). The test signal takes the same path as the main signal received from the antenna 114 inside the 0-system receiver 133.

  In step 311, the base station control unit 113 requests the 0-system receiver 133 to report the S / N of the received test signal. In step 312, the 0-system receiver 133 demodulates the test signal by the PN code demodulator 207 and reports the S / N of the received test signal to the base station control unit 113. In step 313, the base station control unit 113 records the reported received S / N value in the RAM 138. The value recorded here is “reflection direction S / N”.

  In step 314, the base station control unit 113 instructs the test signal generation unit 220 to stop the test signal transmission. In step 315, the receiver test circuit 220 stops the operation of the PNGEN 221 and stops the test signal transmission.

  In step 316, the base station control unit 113 performs normality diagnosis of the receiver using the reception S / N values recorded in steps 308 and 313. Normal diagnosis is performed according to the following procedure.

(1) If the forward S / N recorded in the normality confirmation RAM 138 of the 0-system receiver 133 is within a specified range (predetermined range defined by the specification) from the expected value, it is determined to be normal, and if not, it is determined to be abnormal. Note that the expected value of the forward direction S / N is calculated as follows. When a test signal with a signal power of Pin [dBm] in terms of the reception antenna end is input to a receiver with a gain of G [dB], a noise figure of N [dB], and a reception bandwidth of BW [Hz], The expected value of the forward direction S / N is as follows.
Expected forward S / N value = Pin-10log (kT (BW)) + N
= Pin − (− 174 + 10 × log (BW)) + N [dB]
However, -174 [dB] in the above equation is a value converted to dBm, where k is a Boltzmann multiplier and T is normal temperature (300K).

(2) Normality confirmation of receiving antenna 114 (VSWR measurement)
Using the values of the forward direction S / N and the reflection direction S / N recorded in the RAM 138, the antenna VSWR is calculated as follows.
RL (Return Loss) = reflection direction S / N−forward direction S / N [dB]
VSWR = (1 + 10 ^{(RL / 20)} ) / (1-10 ^{(RL / 20)} )
If the calculated VSWR is within a specified range (predetermined range defined by the specification), it is determined to be normal and if not, it is determined to be abnormal.

  In step 317, the base station control unit 113 reports the diagnosis result to the maintenance terminal 103. The diagnosis result includes, for example, information (for example, sector and system) for identifying the receiver that has performed the diagnosis, a received S / N value, a VSWR value, and / or a receiver failure stored in the RAM 138. It can include information indicating whether or not. The maintenance terminal 103 receives the diagnosis result, displays the received diagnosis result on the display unit and / or stores it in the storage unit, and ends the diagnosis.

  According to this embodiment, normality confirmation of a wireless receiver can be realized easily and at low cost. Further, the normality confirmation of the receiver and the antenna according to the present embodiment does not affect the receiver in service operation.

  100: wireless base station, 101: terminal, 102: network, 103: maintenance terminal, 110: wireless signal transmission / reception unit, 111: modulation / demodulation signal processing unit, 112: line interface unit, 113: base station control unit, 114: 0 System antenna, 115: 1 system antenna, 120: downlink radio signal, 121: uplink radio signal, 122: downlink radio signal, 123: 0 system uplink radio signal, 124: 1 system uplink radio signal, 125: downlink baseband signal, 126: 0 system upstream baseband signal, 127: 1 system upstream baseband signal, 128: data, 130: DUP (duplexer), 131: BPF (bandpass filter), 132: transmitter, 133: 0 system receiver, 134: 1 system receiver, 135: modulator, 136: demodulator, 201: 0 system LNA (low noise amplifier), 202: 0 system BPF Band pass filter), 203: 0 system AMP (amplifier), 204: 0 system ADC (A / D converter), 205: 0 system RX-BB (reception baseband), 206: 0 system RX baseband main signal processing 207: 0 system PN signal demodulator, 211: 1 system LNA (low noise amplifier), 212: 1 system BPF (bandpass filter), 213: 1 system AMP (amplifier), 214: 1 system ADC (A / D converter), 215: 1 system RX-BB (reception baseband), 216: 0 system RX baseband main signal processing unit, 217: 0 system PN signal demodulator, 220: test signal generation unit, 221: PNGEN ( PN code generator), 222: DAC (D / A converter), 223: SW (high frequency SW), 225: 0 system CPL (0 system directional coupler), 226: 1 system CPL (1 system directional coupling) ), 240 Path of the test signal (forward), 241: path of the test signal (reflection direction).

Claims (2)

A directional coupler connected to the antenna,
A test signal having a PN code generation circuit that generates a PN code, a DA converter that converts the generated PN code into a test signal that is a spread spectrum signal, and a switch that guides the test signal to the directional coupler Generator,
A receiver including a PN code demodulator that measures a forward S / N of the test signal input through the directional coupler and passed through the same path as the main signal input from the antenna; and
A control unit for determining whether the measured forward direction S / N is within a first predetermined range;
Further, the PN code demodulator included in the receiver is inputted through the directional coupler, reflected by the antenna, and passed through the same path as the main signal inputted from the antenna. Further measure the reflection direction S / N,
The control unit determines whether or not the VSWR of the antenna obtained from the measured forward direction S / N and the reflection direction S / N is within a second predetermined range. A wireless receiver. A test method for an antenna and a radio reception apparatus that receives a main signal input from the antenna,
Control a test signal supplied via a directional coupler to the connection end of the radio receiver with the antenna;
Measuring a forward S / N of the test signal supplied through the directional coupler and passing through the same path as the main signal input from the antenna;
Determining whether the measured forward S / N is within a first predetermined range;
Further, the reflection direction S / N of the test signal input through the directional coupler, reflected by the antenna, and passed through the same path as the main signal input from the antenna is further measured.
It is determined whether or not the VSWR of the antenna obtained from the measured forward direction S / N and reflection direction S / N is within a second predetermined range. Equipment test method.

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